WHO-HAEM4R, ICC and WHO-HAEM5 all include histiocytic and dendritic cell neoplasms, with similar or identical nomenclature, although Rosai Dorfman Disease and ALK + histiocytosis, neither of which were included in WHO-HAEM4R, are included in both ICC and WHO-HAEM5 (Table 5). Here, ALK is linked to intrahepatic cholangiocarcinoma.